Polydora ciliata in variable salinity infralittoral firm mud or clay

SS.IMU.EstMu.PolVS

SS.IMU.EstMu.PolVS recorded () and expected () distribution in Britain and Ireland (see below)

Marine natural heritage importance

Listed under

EC Habitats Directive

National importance

Not available

Habitat Directive feature (Annex 1)

Estuaries

Biotope importance

Polydora ciliata is a serious pest of oysters and mussels, but invades only the shell and does not eat the soft tissue. When infestation is heavy, the shell is weakened and this makes the mollusc more susceptible to predation by crabs. Occasionally, the inner surface of the shell is damaged by the worms and the mollusc secretes a nacreous substance to seal the perforation. The resulting blisters are an indication of attack by the species, and mussels heavily infested with the polychaete have reduced flesh content, possibly as a result of some impact on the metabolism of the mussel.

Exploitation

The biotope is unlikely to be exploited because Polydora ciliata is of no commercial interest.